Sailfin Catfish from the Amazon Relocate to the Ciliwung River: Here's the History

The sailfin catfish has recently become a topic of discussion. This is because the DKI Jakarta provincial government is conducting a mass cull due to the increasing population of the fish in rivers in the capital city.

In fact, the sailfin catfish or Pterygoplichthys pardalis is not native to Indonesia. This animal originates from far away in South America, specifically in the Amazon River.

An article by doctoral student in Biology at Gadjah Mada University, Alfian Primahesa, published on The Conversation website, states that the sailfin catfish has a body covered in a hard, spotted layer. This protection allows the fish to survive in its extreme native habitat.

In the book “Yuk Mengenal Ikan Sapu-sapu Sungai Ciliwung” by Dewi Elfidasari, it is mentioned that the sailfin catfish entered the country through the ornamental fish trade.

Its growth form and attractive appearance make the sailfin catfish known as one of the popular ornamental fish. It is also kept as a pet in aquariums.

Many people keep it as a natural cleaner for ponds or aquariums. The fish will be seen at the bottom of the water cleaning its environment.

The book also states that in Indonesia, the sailfin catfish plays a role in eating leftover feed, algae or moss, and remains of dead biota in the waters.

The high interest in the sailfin catfish has led to it being imported directly from South America. The book describes it as an intentional introduction from other regions or countries.

Over time, the fish has undergone changes in body size and increased food consumption ability.

The sailfin catfish no longer only consumes moss and algae, but also the eggs of other fish species in the same pond.

This behaviour has also led to the sailfin catfish being released into several freshwater bodies, including the Ciliwung River. Even in a new place, the sailfin catfish has high adaptability, including to places with low oxygen levels and pollution.

In the Ciliwung itself, its population continues to increase. Ultimately, it has negative impacts and is called an invasive species that affects human health, the natural environment, and the economy.

Lecturer in Aquaculture at the Faculty of Fisheries and Marine Sciences, University of Airlangga, Veryl Hasan, explains that local fish cannot survive in damaged river conditions. In contrast, the sailfin catfish can survive and causes its population to explode.

Dangers of Sailfin Catfish in Jakarta

Veryl highlights the presence of species like the sailfin catfish entering Indonesian waters without adequate natural predators. The fish can also displace local fish.

The sailfin catfish can utilise almost all resources in the river, as well as create intense competition for food and survival with local fish.

“When outside its native habitat, the sailfin catfish can displace local fish. Because few organisms prey on it, its population grows without significant barriers,” he explained.

This is different when the sailfin catfish is in a healthy environment. Because the fish, known as pleco, must compete with many other local fish.

Veryl emphasises the need for enforcement of rules regarding the prohibition of releasing foreign fish into rivers. This includes conducting supervision and actions in the field.

This problem is not just about catching the sailfin catfish. But it also requires restoring the river water quality.

In that way, more local fish can survive and balance the ecosystem. “The key is not just catching the sailfin catfish, but also improving the river habitat,” he stressed.